1. Field of the Invention
The present invention relates to a method of driving a plasma display panel in accordance with a matrix display scheme, and a plasma display apparatus.
2. Description of the Related Art
In recent years, a variety of thin display devices have been brought into practical use in response to demands for thinner display devices with the trend of an increase in screen sizes thereof. A plasma display panel (hereinafter referred to as the xe2x80x9cPDPxe2x80x9d) has drawn attention as one of thin display devices, which comprises a plurality of discharge cells arranged in matrix for carrying pixels. In this plasma display panel, since each discharge cell emits light by discharging, it can represent only two levels of luminance, i.e., a xe2x80x9clit statexe2x80x9d in which the discharge cell emits light at a predetermined luminance, and an xe2x80x9cunlit state.xe2x80x9d Thus, a subfield method is employed to implement gradation driving for providing halftone display luminance levels corresponding to an input video signal for a PDP comprised of the discharge cells as described above.
The subfield method involves dividing one field display period into N subfields, and allocating to each of the N subfields a number of times discharge cells are continuously discharged. Each subfield includes an addressing stage which is executed to selectively discharge each of discharge cells in accordance with an input video signal to set the discharge cell in either a xe2x80x9clit discharge cell statexe2x80x9d or an xe2x80x9cunlit discharge cell state,xe2x80x9d and a light emission sustain stage which is executed to repeatedly discharge only discharge cells in the xe2x80x9clit discharge cell statexe2x80x9d the allocated number of times to emit light. According to this driving method, an intermediate luminance is represented in accordance with a total number of discharges performed for emitting light in each light emission sustain stage within one field display period.
In the plasma display apparatus, the discharge cells are discharged not only in the light emission sustain stage for actually displaying an image but also in the addressing stage, so that the discharge cells consume the power in accordance with currents which flow associated with the discharges. In this case, whether each discharge cell discharges or not in the addressing stage depends on an input video signal. Therefore, depending on an input video signal which specifies an image to be displayed, a problem arises in that the power consumed in the addressing step is increased.
The present invention has been made to solve the problem mentioned above, and it is an object of the invention to provide a plasma display panel driving method and a plasma display apparatus which are capable of saving the power consumption.
A plasma display panel driving method according to the present invention is provided for driving a plasma display panel including a plurality of discharge cells carrying display pixels based on a video signal. The method includes an addressing stage for generating a selective discharge at least once for setting each of the discharge cells to a lit discharge cell state or an unlit discharge cell state in accordance with pixel data based on the video signal, and a light emission sustain stage for causing only the discharge cell in the lit discharge cell state to repeatedly discharge, wherein the number of times of the selective discharges generated in the addressing stage is changed in accordance with power consumption associated with the selective discharge.
In addition, a plasma display apparatus according to the present invention has a plurality of row electrode pairs corresponding to display lines and a plurality of column electrodes arranged to intersect with each of the row electrode pairs, and discharge cells each formed at each of intersections of the row electrode pairs and the column electrodes for carrying a pixel, wherein one field display period includes N subfields each comprised of an addressing period and a light emission sustain period for driving the plasma display panel. The plasma display apparatus includes an address driver for generating a pixel data pulse for selectively discharging the discharge cells in the addressing period of one subfield in the N subfields and each of subfields subsequent to the one subfield and consecutive to each other to set the discharge cell to a lit discharge cell state or an unlit discharge cell stage, and applying the pixel data pulse to the column electrodes, a sustain driver for repeatedly applying a sustain pulse to the row electrodes in the light emission sustain period in each of the subfields to repeatedly discharge only the discharge cells set in the lit discharge state to sustain light emission, address driver power measuring part for measuring power consumed by the address driver, and address power control part for changing the number of times the selective discharge is generated in a subfield subsequent to the one subfield in accordance with the power consumption.